<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>参考链接：https://codepen.io/xboxyan/pen/JjMWQBP</title>
</head>
<style>
  body {
    display: grid;
    place-content: center;
    height: 100vh;
    margin: 0;
  }

  clock {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 380px;
    height: 380px;
    font-size: 24px;
    border-radius: 20px;
    box-shadow: 2px 2px 20px rgba(0, 0, 0, .1);
    --step: 60s;
  }

  clock::before {
    content: '';
    position: absolute;
    width: 300px;
    height: 300px;
    border-radius: 50%;
    background: repeating-conic-gradient(from -.5deg, #333 0 1deg, transparent 0deg 30deg), repeating-conic-gradient(from -.5deg, #ccc 0 1deg, transparent 0deg 6deg);
    -webkit-mask: radial-gradient(transparent 145px, red 0);
  }

  clock-pane {
    width: 250px;
    height: 250px;
    position: absolute;
  }

  num {
    position: absolute;
    offset-path: path('M250 125c0 69.036-55.964 125-125 125S0 194.036 0 125 55.964 0 125 0s125 55.964 125 125z');
    offset-distance: calc(var(--i) * 10% / 1.2 - 25%);
    offset-rotate: 0deg;
  }

  hour {
    position: absolute;
    width: 4px;
    height: 60px;
    background: #333;
    transform-origin: center bottom;
    transform: translateY(-50%) rotate(0);
    animation: clock calc(var(--step) * 60 * 12) infinite linear;
    animation-delay: calc(-1 * var(--step) * var(--dh) * 60);
  }

  min {
    position: absolute;
    width: 4px;
    height: 90px;
    background: #333;
    transform-origin: center bottom;
    transform: translateY(-50%) rotate(0);
    animation: clock calc(var(--step) * 60) infinite linear;
    animation-delay: calc(-1 * var(--step) * var(--dm));
  }

  sec {
    position: absolute;
    width: 2px;
    height: 120px;
    background: red;
    transform-origin: center bottom;
    transform: translateY(-50%) rotate(0);
    animation: clock var(--step) infinite steps(60);
    animation-delay: calc(-1 * var(--step) * var(--ds) / 60);
  }

  sec::after {
    content: '';
    position: absolute;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    left: 50%;
    bottom: 0;
    background: #fff;
    border: 4px solid #333;
    transform: translate(-50%, 50%);
  }

  @keyframes clock {
    to {
      transform: translateY(-50%) rotate(360deg);
    }
  }
</style>

<body>
  <clock id="clock">
    <clock-pane>
      <num style="--i:1">1</num>
      <num style="--i:2">2</num>
      <num style="--i:3">3</num>
      <num style="--i:4">4</num>
      <num style="--i:5">5</num>
      <num style="--i:6">6</num>
      <num style="--i:7">7</num>
      <num style="--i:8">8</num>
      <num style="--i:9">9</num>
      <num style="--i:10">10</num>
      <num style="--i:11">11</num>
      <num style="--i:12">12</num>
    </clock-pane>
    <hour></hour>
    <min></min>
    <sec></sec>
  </clock>
</body>
<script>
  const d = new Date()
  const h = d.getHours();
  const m = d.getMinutes();
  const s = d.getSeconds();
  clock.style.setProperty('--ds', s)
  clock.style.setProperty('--dm', m + s / 60)
  clock.style.setProperty('--dh', h + m / 60 + s / 3600)
</script>

</html>